1) because of the heavy rain last sunday, our picnic was cancelled.

- cấu trúc : because of + N/ving ,......

2) if you don't work hard, your parents will be unhappy ( câu điều kiện) 

- cấu trúc: if + S + V, S + will/can/may + V

3)unless you keep your feet dry, you will catch a cold ( câu điều kiện )

- cấu trúc: unless + S + V, S + will/can/may + V

4)He has worked as a computer programmer for 5 years ( present perfect ) 

- cấu trúc : S + has/have + v3/ed ....... 

CHÚC HỌC TỐT :D 

`1.` Because of the heavy rain last Sunday, our picnic was led.

`-` Because `+` S1 `+` V `+ ...` , S2 `+` V `+ ...`

`=` Because of `+` Ving/N, S2 `+` V `+ ...`

`->` Dùng để chỉ nguyên nhân của hành động

`2.` If you don't work hard, your parents will be unhappy

`-` V-inf `+` or `+` S `+` will `+` V-inf

= If you don't `+` V-inf, S `+` will `+` V-inf

`-` Don't `+` V-inf `+` or `+` S `+` will `+` V-inf

= If you `+` V, S `+` will `+` V-inf

`3.` Unless you keep your feet dry, you will catch a cold.

`-` Unless `=` If not

`-` Cấu trúc câu điều kiện loại I: If `+` S1 `+` V(s/es), S2 `+` will/can `+` V-inf

`-` catch a cold: bị cảm lạnh

`4.` He has worked as a computer programmer for 5 years.

`-` start `+` Ving: bắt đầu làm gì

`-` Cấu trúc thì HTHT: S `+` have/has `+` Vpp (DHNB: for 5 years)